1. Field of the Invention
The present invention relates to a printing device such as a printer or copier and, more particularly, to an apparatus for cleaning a transfer roller and an optical photoreceptor of a printing device, which is intended to clean the transfer roller for transferring a toner image formed on the optical photoreceptor to a recording paper.
2. Description of the Related Art
In general, a printing device such as a printer or copier is an apparatus which forms a latent electrostatic image on an optical photoreceptor such as a photosensitive drum, or photosensitive belt, develops the latent electrostatic image with toners of predetermined different colors and then forms a desired image by transferring the developed image to a recording paper. Such printing devices are classified into dry type and wet type devices according to the type of toner used. In the case of the dry type device, toner in a powder state is used, and in the case of the wet type device, liquid ink in which volatile liquid carrier is mixed with a toner is used. Since the wet type device exhibits a higher quality print than the dry type device, and, in addition, inhaling harmful toner dust can be prevented in the wet type device, the wet type device is being used increasingly.
FIG. 1 shows a schematic diagram illustrating the structure of a conventional printing device.
Referring to FIG. 1, a conventional printing device comprises a photosensitive belt 10 installed along a continuous loop track, a driving roller 11 for circulating the photosensitive belt 10 along the given track, a backup roller 12, and a tension roller 13.
A main charger 20 is provided over one side of the photosensitive belt 10 for charging one surface of the photosensitive belt 10 to a predetermined voltage. In addition, laser scanning units 30 each for irradiating a laser beam on the photosensitive belt 10 to form a latent electrostatic image, and developing units 40 each for developing the latent electrostatic image to form a toner image by applying an ink of a toner of a predetermined color and a liquid carrier to the region where the latent electrostatic image is formed are installed under the photosensitive belt 10. The plurality of laser scanning units 30 and the plurality of developing units 40 are installed for color printing so that latent electrostatic images corresponding to the respective colors can be developed as shown in FIG. 1.
The ink thus applied to the photosensitive belt 10 by the developing units 40 is dried by a drying roller 51 and heating rollers 52, and accordingly the liquid carrier contained in the toner image is removed. The toner image is transferred to a recording paper P by a transfer roller 61 installed parallel to the backup roller 12 with the photosensitive belt 10 therebetween. The recording paper P is supplied between the transfer roller 61 and a fixing roller 62 installed with a predetermined space from the transfer roller 61 to be parallel to the transfer roller 61, and the toner image, which is transferred to the recording paper, is heated and pressed by the fixing roller 62 and is fixed to the recording paper P to form a desired image.
On the other hand, the toner image transferred to the transfer roller 61 is not completely transferred to the recording paper P in the transfer step, and the transfer roller 61 on which a minute quantity of toner particle remains may perform the following transfer job. In addition, micro-dirts, dust particles, or the like may adhere to the surface of the transfer roller 61 in a paper P transferring step. Since such remaining toner particles, i.e., waste ink, microscopic dirt, or dust particles stain the surface of the transfer roller 61, there is a problem in which as printing operations are repeated, it is difficult to form a clear and crisp image on the recording paper. In addition, when a paper jam in which a recording paper P is abnormally inserted between rollers or a similar problem occurs, the operation of the printing device is stopped, and accordingly the toner image on the surface of the transfer roller 61 is not completely transferred to the recording paper P and remains on the transfer roller 61. Since the toner image thus remaining on the surface of the transfer roller 61 stains the next recording paper, there is a problem in which recording papers are unnecessarily consumed.